1985 Wishbone options: std / neg camber / wide track

[Caterham BDR]

Hi All,

I'm new to the world of Caterhams and we have recently purchased a 1985 BDR. We're in the process of getting it fixed up and wanted to get the front suspension sorted.

I have read up on the front wishbone options. After speaking with a couple of other owners I'm keen to do a 1 piece top wishbone (adjustable camber) as the car currently has the ARB locating the top link. I'm aware that I need to use the correct top ball joint (QR1118S).

The car is a live axle (ital) rear end.

My main question is: Do you think it is worthwhile installing the wide track front end or just sticking to the 1-piece top wishbone standard track setup?

The wide track lower wishbone has a spherical bearing rather than the trunnion arrangement. Can this be adapted to my current uprights? or would the uprights need to be replaced? I'm keen to keep the existing 95.25 PCD.

How much additional neg camber do the std track negative camber lower arms give? I have read that these have to be used with the different top wishbones?

We will probably go with a set of the 1-way Nitrons from Meteor Motorsport and he mentioned going the wide track would mean a longer damper giving a bit more room for all the damper internals (but not essential). 

Car will be used on dry roads and do some track days.

Thanks, Chris

[7 wonders of the world]

Tazio had an interesting time with the same scenario on his BDR, due to manufacturing tolerance there was quite a variation in camber left to right, cant remember what option he finally went for but I'm sure he will be along soon.

 

[Piers300]

Have you made contact with Red Line Components. They are the official 7 parts distributor for older 7’s and will probably have all the bits in stock. Speak or email to Chris. 

[Tazio]

Chris ( Mr Caterham BDR) and I have been messaging for a while, in the end, because i wanted to keep mine more or less original, and because I had clam shell wings, stayed narrow track

Due to manufacturing issues with one of my new top links, and for originalities sake I opted for the following:-

Retained the original spec bottom wishbones, and uprights including the trunnions.  I replaced the whole top wishbone, and arb arrangement for the later complete wishbone assembly, remembering that the swivel joints in the wishbones had to be replaced as the taper in the original trunnion uprights is different. From memory the joints come from a Fiat 132.

If I was building a front end and didn't care about originality and had cycle wings, then I would go widetrack, but this necessitates new uprights too.  It raises a couple of issues though, on the early chassis the bottom wishbones do not have any integral bushes for the front chassis mounting, they use Type Y bushes and the wishbone fixes on a peg, so if this peg arrangement is retained what bushes would you use on the bottom wishbone?  Secondly does the later upright stub axle take the earlier hub arrangement? I don't know the answer to that. Also don't forget you would need steering rack extensions too.

[Caterham BDR]

Yes Hi Alan! Were happy to alter the suspension a little, but it would be nice to keep the option of going back to the original suspensions in future if possible.

 

Alan has a later car (with De Dion suspension?) and I understand wide track is a fairly easy decision if you are replacing all the suspension anyway.

 

What about for my live axle car? Can a wide track front end create too much front grip? Or would it help manage the roll and therefore give the rear end more grip too?

[Tazio]

Re just changing out just the original top link, arb arrangement for the later full wishbone and new arb set up, on my BDR it had a positive improvement, in feel, felt more positive and allows for camber adjustment.

With regard to widetrack, the only personal experience I have is changing from narrow track to widetrack on one of the original Vauxhall HPCs, which were prone to understeer due to the weight of the engine. The change made a significant improvement, like chalk and cheese.  If you are just using the BD as a road car, personally I wouldn't think the change is worthwhile.